Lift-bridge.



C. G. E. LARSSON.

LIFT BRIDGE.

APPLIOATION FILED JUNI: 24, 190s.

1,124,922. Patented 11111121915.

3 SHEETS-SHEET 1.

1HE NORRIS PETERS CO.. PHUTO-LITHO.. WASHINGTON. D. CA

C. G. E. LARSSON.

LIFT BRIDGE.

APPLICATION FILED JUNI; 24, 1908.

1,124,922. Patented Jan. 12, 1915.

s SHEETS-SHEET 2.

I IIIIIIII III ||II l IIIIIIIIIIIHIII IIIIIIIIIIIIII IIIIIv IHI IIIIHIII maAa/vl @WM THE NORRIS PETERS CO.. PHOTO-LIHO.. WASHINGTON, D. C.

G. G. E. LARSSON.

LIFT BRIDGE.

APPLICATION FILED JUNE 24, 1908.

Patented Jan. 12, 1915.

3 SHEETS-SHEET 3.

THE NDRRIS PETERS C0.. PHD'YYLLITHO.. WASHING TN. n, "7.

CARL eUsTAE EMIL LAEssoit, or NORTH PLAINEIELD, NEW JERSEY.

LIFT-BRIDGE.

I Specication of Letters Patent. Patented Ja,n 12,` 19615.

Application mea Junel 24, 190s. Serial no. 440,138.v

To all whom imag concern.'v A. I

Be it known that I, CARE GUs'rAr EMIL LlmssoN', of North Plainfield, inthe county of Somerset and State of New Jersey, a sub# ject of the Kingof Sweden, have invented a new and useful Improvement in Lift- Bridges,of which the following is a specifif cation, reference being had to theaCCOmpanying drawings, forming part of this specification, in which'- 6is a side elevation, partly in horizontal section, showing the bridgeoperating motor applied to the bridge; and Fig. 7 is a plan view, partlyin horizontal'section, showing the motor.

Referring to the drawings, 2 represents the lift bridge, which may be anordinary span, supported at one end on horizontal pins 3 so placed thatwhen the span revolves on the axis of the pins 3 it will clear theadjoining structure; and at theother end, when in horizontal position,the span rests upon a support 4. The bridge is adapted to be swung in avertical plane on the axis 3 from the horizontal position shown in Fig.1 to the elevated position shown in Fig. 3.

The lixed frame 4 at the end of which the bridge 2 is pivoted, rests atone end against the shoe 3 which carries the pivot 8, and at the otherend is fastened to a xed pier or support 5. l

The lifting mechanism of the bridge comprises a cylinder 6, which in thedrawings I show pivoted to the frame 4 on horizontal trunnions 7.y Thiscylinder is made' telescopic, having one or more internal cylinders 8, 9and a piston 10, which is connected by pins or trunnions 10 with aconnecting or pull member 11 extending to the bridge 2, to which it isconnected by a pin 12. The member 11 is also supported on extensions 7from the trunnions 7 which fit between` y guideways 13 on the member 11;and the cylinders 6, 8 and 9 also travel on the guideways 13. Thecylinders 6 and 9, respectively, are connected to a differentialcylinder 14 by pipes 15 and 16, these pipes being jointed in order toprovide for movement;

and the cylinders 8 and 9 have stops 17 which limit their motion tothedesired vexadapted in the ordinary way for holding the liquid with whichthe cylinders are operated; andin the case shown in the drawings,wherethe cylinders are operatedby com;- pressed air or gas, it is madestrong enough to contain the pressure required for lifting the bridge."The differential cylinder'` and accumulator may be constructed invarious ways, and the dierential cylinder is connected with a. pump 20and provided with pipes 21, 22, 23, as shown.

The operation is as follows: Assuming that the bridgeis in the positionshown in Fig. 1, that the piston 18 in the differential cylinder 14 isnear the top of the cylinder, and that the parts of the cylinder 6 andits plunger are as shown in F ig. 6; to open the bridge the lvalves areclosed in the pipes 21 and 23 and are opened'in' the pipes 22 and 24.vThis will admit pressure into the cylinder 6 and will force thecylinders 8 and 9 and the plunger 10 outwardly, displacing liquid fromtheV piston-rod end of the cylinder 9 into the upper end of thedifferential cylinder 14. The motion of the plunger 10, acting throughthe connecting `member 11 will draw the bridge 2 into an uprightposition.

To close`the 'bridge the pipes'24 and 22 are closed and the pipes 21 and23 are opened. The pressure is thus taken from the cylinderV 6 and thecylinder 9 in front of the piston `is put into communication with thelower (power) side of the differential cylinder 14. -This, together withthe weight of the bridge,'will draw the bridge down to a horizontalposition, exhausting the Huid through the pipe 15 into the up- 24 havingsuitable valves f per (low pressure) end of the differential cylinder14, and as the area of the top of` the piston 18 is greater than.thearea of its lower side, by reason ofthe projection ofthepistonthrough the end of the cylinder, the piston will be moved therebyand the fluid exhausted by the cylinders, 8 and 9 `will be forced intothe upper end of the differential cylinder. The bridge is thus made todo work in closing by restor as to force the piston upwardly to the position shown in F ig. 1.

By means of my invention the bridge 2 operates as a simple span whenclosed, resting upon the supports 3 and el, and as shown is without anysubstantial movable counter'- weight, so that it is raised solely by theaction of the cylinders and is lowered mainly by gravity," and whenlowered it is useful for work in restoring in part the pressure requiredto raise it.

The foregoing description presupposes that the member 1l and cylinders6, 8, 9, an'dpiston rod 10 are made long enough to allow the span 2 tocome to a bearing at l when the bridge is let down. If, however, thesemembers are shortened some and made strong enough the live load can becarried without a support at 4. On this principle I can build twospansand put them up facing each other when I would get a clear riveropening of twice as much as before. The drawings indicate` the operatingcylinder in the member 11. It can also be placed in either of themembers constituting the frame 4.

The bridge is novel in that it dispenses with the necessity for the useof movable counterweights, and when in closed position fis more stablethan in the ordinary counterweighted bridge.

By employing a telescopic cylinder I employ the greatest amount of forceat the moment when the lifting operation begins and a succeedinglylesser amount of force as the span is lifted. If a non-telescopiccylinder is used, the same amount of force needed at the beginning ofthe operation would be used at the end of the operation, although a muchsmaller amount would be required.

I claim as my invention: y

l. A' lift bridge,a motive cylinder,a pull member in which the cylinderis positioned land which is adapted to be upwardly and rearwardly drivenfor opening the bridge by the said cylinder, said cylinder being heldagainst rearward movement by a pivotal support.

2. The combination with a pivoted bridge, of a fixed support, a motivecylinder connected to said support, and a pull member connected to thebridge and to the piston of the cylinder, said pull member embracing thecylinder and being movable endwise about the same; substantially asdescribed.

In testimony whereof, I have hereunto set my hand.

C. G. EMIL LARSSON. Witnesses:

THOMAS W. BAxEwnLL, ANNA E. VALLACE.

Copies of this patentrmay bel obtainedfor ve cents each, by addressingthe Commissioner of Patente.

, Washington, D. C.

